Method for producing a ductwork damper, ductwork damper, and ductwork damper unit incorporating same
A method for producing an air duct damper includes the steps of punching from sheet metal stock a damper preform having a body and two diametrically opposed arms extending from opposite sides of the body; and forming an indentation in the damper preform extending between and up to respective ends of the two arms.
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This application is a national phase of PCT application No. PCT/US2020/033859, filed May 20, 2020, which claims priority to U.S. provisional patent application No. 62/3850,020, filed May 20, 2019, all of which are incorporated herein by reference hereto.
FIELD OF THE INVENTIONThe present invention relates to improved dampers for pivotal mounting in cooling and heating ductwork.
BACKGROUND OF THE INVENTIONConventional heating, ventilating and air-conditioning (HVAC) systems utilize vast lengths of sheet metal duct work to convey conditioned air throughout buildings of all types, including residential, industrial, office, medical and apartment buildings. Such HVAC systems include a great many pivotable damper blades situated in air ducts at selected locations to facilitate adjustments at the air flow as required.
In many conventional circular tube HVAC duct systems, each damper is a circular disk pivotably mounted via bearing elements mounted on the side and extending through a set of aligned holes cut in opposite facing side walls of duct segments. Typically, two bearing elements are mounted on opposite peripheral edge regions of the disk. These pivot elements allow the damper blade to pivot from a closed position in which it substantially blocks the air flow to an angled position in which it permits different degrees of airflow.
Known air duct dampers have numerous components and/or are complicated to produce. The present invention seeks to significantly reduce the number of components in a damper blade and to reduce the cost of manufacture by more efficient use of material to produce the damper plates.
SUMMARY OF THE INVENTIONAccording to one aspect of the invention, a method for producing an air duct damper includes stamping from sheet metal stock a damper preform having a body and two diametrically opposed arms extending from opposite sides of the body; and forming an indentation in the damper preform, extending between and up to respective ends of the two arms.
The indentation extending between the ends of the arms provides rigidity to the damper plate and the arms. At the same time, the arms of the damper function as pivots that can be received in correspondingly shaped openings of bushings that are pivotally mounted on opposite side walls of a ductwork section.
The indentation can have different cross-sectional shapes. In one embodiment, the indentation has a substantially v-shaped cross section. In this case the arms have a v-shaped cross section and can be received in bushings with a corresponding v-shaped through opening.
According to another advantageous embodiment, the indentation has a c-shaped or semicircular cross section. In a particularly advantageous variant, the ends of the c-arms with the c-shaped or semicircular cross section can be provided with external threads. In this way, the arms can be secured in the corresponding through-openings of the bushings by threadably engaging a nut with corresponding internal threads on the external threads of the arms.
In an embodiment, the c-shaped or semicircular cross section of the arms can also be achieved by first forming the preform with an indentation having a v-shaped cross section and then forming the arms so as to have a c-shaped or semicircular cross section.
In another embodiment, the indentation can be formed simultaneous with the stamping of the preform.
According to another aspect of the invention, a bushing for pivotally mounting a damper to a section of ductwork for directing conditioned air in a predetermined direction, includes a member made of a soft pliable material, and having a generally circular outer periphery, the member defining a peripheral groove over at least a portion of the periphery for attachment of the member to a section of the ductwork by insertion into an opening in the ductwork, the opening preferably being of diameter at least equal to, or generally less than the inner diameter of the peripheral groove.
A generally central opening extends through the center of the soft pliable member for engaged reception of a pivot arm of the damper, for permitting the damper to be pivoted relative to the ductwork while the bushing rotates smoothly relative to the ductwork.
The bushing can be made of a natural or synthetic rubber material, although such materials are not considered to be limited. Silicone rubber or any synthetic rubber material is preferred.
The generally central opening in the bushing member is preferably tapered, with the opening of lesser dimension on one side being less than the corresponding dimension of the pivot arm of the damper plate, to thereby provide an airtight seal therebetween when the pivot arm is inserted into the opening.
The tapered opening in the bushing is such that one side is dimensioned to snugly receive the pivot arm, and the opposite side is of slightly less dimension than the pivot arm. Upon assembly, when the pivot arm is inserted into the opening (i.e., preferably through the larger end for ease of insertion) a small outward force will be applied by the pivot arm to the body of the bushing member when it reaches the smaller end of the tapered opening in the bushing member. This force will cause the bushing material to expand radially outwardly thus increasing the already tight fit between the periphery of the bushing and the ductwork, thereby improving the seal therebetween.
Preferably, the bushing for pivotally mounting a damper to a section of thin sheet metal ductwork comprises a member made of a soft pliable silicone rubber material, and defining a generally longitudinal axis, the member having a first section of generally circular configuration, preferably monolithically formed with a second section of similar generally circular configuration, the first section having an outer diameter greater than the diameter of the second section to define a radially extending generally annular surface of the first section extending circumferentially around the second section. It is foreseeable that the first section can be of shape other than circular without departing from the invention. For example, the first section can be square while still functioning to retain the bushing member in position in the ductwork.
At least two diametrically opposed lips (or “ears’) extend radially outwardly from the second section and adjacent the first section, each such lip being longitudinally spaced from the annular surface of the first section. However, it should be appreciated that these lips (or “ears’) are provided in the preferred embodiment, and that an embodiment which does not include such lips can function without departing from the invention. In such case the groove will perform most of the retention function, and therefore, can optionally be made deeper than in the embodiment with the lips.
A groove extends about the periphery of the second section adjacent the annular surface of the first section, the thickness of the groove in the longitudinal direction being approximately equal in dimension to the thickness of the ductwork sheet metal, and the inner diameter of the groove being equal to, or preferably slightly greater than a corresponding dimension of the aperture in the ductwork intended for insertion of the bushing member, for resilient engaged reception of the bushing member therein, whereby the bushing member may be securely attached to the ductwork by reception of the ductwork in the groove and by retention of the ductwork between the annular surface of the first section and each radially upstanding lip of the second section. As will be explained hereinbelow, the thickness of the groove in the bushing can be somewhat greater than the thickness of the ductwork sheet metal. In such case, it is preferable that the diameter of the groove provides a tight fit between the bushing member and the ductwork.
It is envisioned that the bushing of the present invention can be of two-piece construction, each piece being dimensioned and configured to be assembled with the other piece to appear and function as a one-piece bushing.
Improved ductwork is also disclosed for directing conditioned air in a predetermined direction, which comprises a damper according to the present invention rotatably mounted in the ductwork on bushings constructed according to the present invention, whereby loss of conditioned air between the pivot arms of the damper and the bushing is eliminated due to the unique bushings on which the damper is pivotally mounted.
As noted, the bushing of the present invention is preferably made of a soft pliable flexible and resilient material, such as natural or synthetic rubber. Silicone rubber is preferred, due particularly to its physical characteristics, as well as its capability to be formed and dimensioned within predetermined units. Silicone rubber is a rubber-like material composed of silicone itself a polymer-containing silicon together with carbon, hydrogen, and oxygen. Silicone rubbers are elastomers comprised of either one- or two-part polymers, and may contain fillers to improve properties or reduce cost. Silicone rubber is generally non-reactive, stable, and resistant to extreme environments and temperatures from minus 55° C. (i.e., −55° C.) to plus 300° C. (i.e., +300° C.), while still maintaining its useful properties.
There are also many special grades and forms of silicone rubber, including: Steam resistant, metal detectable, high tear strength, extreme high temperature, extreme low temperature, electrically conductive, chemical/oil/acid/gas resistant, low Smoke emitting, and flame-retardant. A variety of fillers can be used in silicone rubber, although most are non-reinforcing and lower the tensile strength.
The silicone rubber contemplated by the present invention may be of hardness in a range of hardness levels, expressed as Shore A or IRHD, between 10 and 100, the higher number being the harder compound. It is also available in virtually any color and can be color matched.
The above and other advantages of the invention will be further described and appreciated by those skilled in the art by reference to the following detailed description of the invention, the claims and the appended drawings in which:
The preform 10 produced in the stamping step is subjected to a forming step in which an indentation is formed in the preform 10 that extends substantially centrally along the central portion 4 from the end 3a of one of the arms to the end 3b of the other arm. As a result of the indentation, the two substantially semicircular portions 1, 2 are positioned closer to each other and together define a substantially circular shape.
The indentation formed in the preform 10 can have different cross-sectional shapes.
In another embodiment, the cross-sectional shape of the arms can be modified after the stamping step. For example, in a further forming step, the arms can be formed so as to have a c-shaped cross section. This makes it possible to provide external threads on the ends of the arms to secure the damper plate in corresponding c-shaped through-openings of bushings by engaging a nut with corresponding internal threads on the threaded c-shaped ends of the damper plate.
In a particularly advantageous embodiment, the indentation formed in the preform has a c-shaped or semicircular cross section. This embodiment is shown in
As shown in
Referring to
In
A peripheral groove 27 extends about the entire periphery of the second section 24 between first section 22 and the second section 24 as shown. This groove 27 receives and interfaces with the sheet metal ductwork 42 as shown in
In the FIGS., the inner diameter of peripheral groove 27 appears to match the diameter of aperture 30 in ductwork 42, a condition which is acceptable. However, in the preferred embodiment, the diameter of aperture 30 formed in the ductwork 42, is preferably slightly less than the initial inner diameter 28 of the peripheral groove 27 (indicated by dash line 28 in
Referring again to
In
Referring again to
In
As noted, the initial taper of opening 36 facilitates convenience of assembly with the damper pivot arm 38, while assuring a tight fit between the pivot arm 3 and at least the opening of dimension “B”. For example, the pivot arm 3 can be inserted into the inner side of opening 36 of greater dimension “C”, ultimately to reach the outer side opening of dimension “B” of lesser dimension, to form a tight seal with the pivot arm 3.
It can be readily appreciated that the snug fit between bushing 20 and ductwork section 42, and between bushing 20 and pivot rod 3, both ensure a significantly improved airtight seal therebetween, while permitting pivotal rotation of the pivot rod 3, as facilitated by the relatively low friction surface of the silicone rubber and the bearing support provided by the bushing member 20.
It should also be appreciated that while silicone rubber is the preferred material for fabricating the bushing, any soft and pliable material may be used, such as synthetic or natural rubber, or other known elastomers.
While the present invention is contemplated for use with conventional ductwork made of thin galvanized sheet metal, of thickness between 0.012 and 0.60 inches, and having a generally tubular configuration of circular cross-section, it may be used with alternative ductwork materials such as plastics, fiberglass, flexible ducting or the like. In addition, the ductwork can be of alternative designs such as ductwork having a rectangular or square cross-section. In such installations the structure which incorporates the damper would necessarily be structured and arranged to facilitate installation of the damper of the present invention and the damper configuration will be arranged to match the ductwork.
Claims
1. A method for producing an air duct damper, comprising:
- stamping, from a sheet of sheet metal stock, a planar, unibody damper preform having a central body and two integral diametrically-opposed arms extending radially from opposite sides of the central body; and
- forming an indentation in the planar, unibody damper preform, the indentation extending longitudinally along an entirety of each of the two integral diametrically-opposed arms and the central body therebetween, wherein forming the indentation causes the two diametrically-opposed arms and the central body to be displaced outwardly from a plane of the planar, unibody damper preform.
2. The method of claim 1, further comprising forming the two integral diametrically-opposed arms so that each one of the two integral diametrically-opposed arms has a c-shaped cross section, and providing an external threading on each one of the two integral diametrically-opposed arms for engagement with an internal threading in a nut.
3. The method of claim 1, wherein the indentation has a v-shaped cross section.
4. The method of claim 1, wherein the indentation has a substantially c-shaped or semicircular cross section.
5. The method of claim 1, wherein the step of stamping the sheet from the sheet metal stock and the step of forming of forming the indentation are performed simultaneously.
6. A damper unit for pivotal attachment to a section of sheet metal ductwork for selectively directing conditioned air in a predetermined direction, which comprises:
- a) a damper plate produced by the method of claim 1; and
- b) a pair of bushings, each of which configured for pivotally mounting a corresponding one said two integral diametrically-opposed arms to the section of ductwork, each of said pair of bushings including: i) a member made of a pliable silicone rubber material, and generally defining a longitudinal axis, said member having a first section of generally circular configuration monolithically formed with a second section of similar generally circular configuration, said first section having a first diameter greater than a second diameter of said second section to define an annular surface extending radially and about a periphery of said second section; ii) at least two diametrically opposed lips extending radially outwardly from said second section and adjacent to said first section, each one of said at least two diametrically opposed lips being longitudinally spaced from said annular surface of said first section and resiliently pivotable about an axis perpendicular to said longitudinal axis; iii) a groove which extends over the periphery of said second section adjacent said annular surface of said first section, a thickness of said groove in a longitudinal direction with respect to the longitudinal axis being sized and dimensioned to receive a thickness of sheet metal forming the ductwork, and an inner diameter of said groove being at least equal to or greater than a corresponding dimension of an aperture in the ductwork for resilient engaged reception of said member therein, wherein said member is securely attached to the ductwork by insertion of the member into the aperture in the ductwork, and reception of the ductwork into said groove, wherein the ductwork is retained between said annular surface of said first section and said groove, and each said at least two diametrically opposed lips of said second section; and iv) a tapered through-opening extending generally centrally and longitudinally through said member, said tapered through-opening being dimensioned for slidable engaged reception with a corresponding one of said two integral diametrically-opposed arms, said tapered through-opening having a cross-sectional shape similar to a cross-sectional shape located at a pivot point of the corresponding one of the two integral diametrically-opposed arms, such that rotation of said two integral diametrically-opposed arms produces a corresponding rotation of said pair of bushings, while each said member is retained in attached rotatable relation with the ductwork to provide bearing support for said corresponding one of the two integral diametrically-opposed arms.
7. The damper unit according to claim 6, wherein a side of said tapered through-opening of lesser dimension of each member is of dimension less than a corresponding dimension of said corresponding one of the two integral diametrically-opposed arms to provide an airtight seal therebetween.
8. The damper unit according to claim 6, wherein said central body has a generally circular shape.
9. The damper unit according to claim 6, wherein said central body has a generally rectangular shape.
10. The damper unit according to claim 6, wherein said central body is generally square.
11. Ductwork for directing conditioned air in a predetermined direction, which comprises:
- A) at least a section of sheet metal ductwork having a generally tubular configuration and a generally circular cross-section; and
- B) a damper unit pivotally mounted to said section of ductwork, which comprises: i) a damper produced with the method of claim 1; and ii) a pair of bushings, each of which configured for pivotally mounting a corresponding one of said two integral diametrically-opposed arms to said section of ductwork, each of said pair of bushings including: a) a member made of a pliable silicone rubber material, and generally defining a longitudinal axis, said member having a first section of generally circular configuration monolithically formed with a second section of similar generally circular configuration, said first section having a first diameter greater than a second diameter of said second section to define an annular surface extending radially and about a periphery of said second section b) at least two diametrically opposed lips extending radially outwardly from said second section and adjacent to said first section, each one of said at least two diametrically opposed lips being longitudinally spaced from said annular surface of said first section; c) a groove which extends about the periphery of said second section adjacent said annular surface of said first section, a thickness of said groove in a longitudinal direction with respect to the longitudinal axis being sized and dimensioned to receive a thickness of sheet metal forming the ductwork, and an inner diameter of said groove being greater than a corresponding dimension of an aperture in the ductwork for resilient engaged reception of said member therein, wherein said member may be is securely attached to the ductwork by insertion of the member into the ductwork-aperture in the ductwork, and reception of the ductwork into said groove, wherein the ductwork is retained between said annular surface of said first section and said groove, and each of said at least two diametrically opposed lips of said second section; and d) a tapered through-opening extending generally centrally and longitudinally of said member, said through-opening being dimensioned for slidable engaged reception with a corresponding one of said two integral diametrically-opposed arms, said through-opening having a cross-sectional shape similar to the cross-sectional shape of said corresponding one of said two integral diametrically-opposed arms, such that rotation of said two integral diametrically-opposed arms produces a corresponding rotation of each said member, while each member is retained in attached rotatable relation with the ductwork to provide bearing support for said two integral diametrically-opposed arms, thereby providing an airtight seal therebetween.
12. The ductwork according to claim 11, wherein said central body of said damper has a generally circular shape.
13. The ductwork according to claim 11, wherein said central body of said damper has a generally rectangular shape.
14. The ductwork according to claim 11, wherein said central body of said damper is square.
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Type: Grant
Filed: May 20, 2020
Date of Patent: Aug 20, 2024
Patent Publication Number: 20210270493
Assignee: Capital Hardware Supply, LLC (Closter, NJ)
Inventor: David Yoskowitz (Woodcliff Lake, NJ)
Primary Examiner: Steven B McAllister
Assistant Examiner: William C Weinert
Application Number: 17/258,781
International Classification: F24F 13/14 (20060101); B21K 1/24 (20060101); F16K 1/22 (20060101);